Not sure how it happened but somehow those advanced inscribers got indestructible (like the illumination wand effect). Also got some console errors - https://pastebin.com/EdSTHRsb
Tried to smack it with the illumination wand to remove it - like ordianary - but didn't do anything.
Fixed it by going into creative and destroying them.

Sorry for not providing more info.

MC 1.12.2 DW20 pack v1.4.0 (added AE2Stuff manually) Forge 14.23.1.2566

It's not super close - should definitely not be in it's range (the two waypoint beacons).

Are there any AE cables that run closer to where the beacon is/was?

Those are the cables - the tree beacons are in every corner of the stone brick fence. As far as I remember, at the time the bug happened, even the one cable that is there now, wasn't present.

Doing further testing at the moment but I am now able to reproduce it every time. It happens when I use the exchanger on the blocks under the tree beacon - more info later (and a video so you can see this black magics first hand LOL)

More info: - Only happens on dedicated server, when I try to exchange blocks under the beacon and the exchanger runs out of blocks that you are trying to replace. That is when the replaced blocks become seethrough aka Astral sorcery illuminated blocks. Then the console throws out errors that I posted before - AE2 insciber corrupt, block/blockfaketree etc. Also the "ghostly" trees (the actual area it should affect) start throwing out inscribers, redstone clocks and droppers - It creates a few copies of said items every time I click with the exchanger under it.

-Gonna try to reproduce in superflat world to eliminate other factors.

Ok, so I managed to reproduce it in a fresh superflat world. Adding video link as soon as it uploads.

https://youtu.be/1ABevWd7VU8
(actual thing is at the end) 9:00 - 10:20

Are you sure you didn't get trolled by someone else on the server?

It's a singleplayer instance, just on a server :D

As far as I know, you can't "illuminate" tile entities anyway so how it came to this beats me.

It happened again a few minutes after restart of the server. After that I removed the AS tree beacon(s) I had next to my house. Another thing is they were acting strangely - found random redstone clocks, machine frames and droppers in the tree canopy? After that It didn't come back (yet) - the original bug this thread is about.

Huh. strange. might be that the treebeacon picked up on wrong places for whatever reason... will investigate this further then..

How close is the tree formed by the treebeacon to this setup? Completely somewhere else or "directly next to it"

Same thing is happening (AE2 Blocks getting corrupt) when I use the formation wand (was using it to flatten the lake in front of the house - not in range of the tree beacon at all.

I did put some extra prevention mechanisms in place and hopefully that'll work out better then - will be included in the next release.